JERUSALEM, Israel -- Israel is facing its greatest dangers in 20 years.

From the Iranian nuclear threat to radical Islamic uprisings in surrounding countries, Israel is increasingly isolated as its enemies are growing stronger.

A nuclear-minded Iran is only part of the problem. Add a weakened United States with the so-called Arab Spring and you get what Prof. Efraim Inbar, director of the BESA Center for Strategic Studies at Bar Ilan University, describes as a serious strategic situation.

"Israel is now in it's worst strategic situation since the end of the Cold War," Inbar told CBN News.

"First of all, the United States is perceived as very weak, particularly during the last year when the U.S. behavior was extremely erratic," Inbar explained. "It ditched some of its allies, such as (ousted Egyptian President Hosni) Mubarak."

Inbar said a weaker United States affects Israel's deterrence.

"Israeli deterrence is not only dependent upon Israeli might but also upon the perceptions that America will come to our help in times of need," Inbar told CBN News.

"And unfortunately the perception now in the Middle East (is) that the United States is not standing by it's allies," he said.

Political change in the Arab world has also brought uncertainty to the region.

"What we see is (the) Islamization of some of the countries, and some of the countries are being fragmented," the professor said.

Israel must beef up its military to counter these threats, Inbar said, because the Jewish state has limited ability to influence the region.

"We have to develop a larger army, a larger navy. We need more money for missile defense and of course for R&D -- research and development -- in order to keep our technological edge over our regional rivals," he said.

Meanwhile, while the world watched the Arab Spring spread through the Middle East, Iran focused on developing its nuclear bomb.

Inbar calls the Iranian nuclear threat the most urgent and dangerous challenge facing Israel today. He said while covert actions have had success, Iran is still making progress.

"Therefore, unfortunately, we are left with the last course, and this is military action to stop the Iranians from getting a nuclear bomb," Inbar told CBN News.

Will Israel take matters into its own hands?

"The feeling in Jerusalem is that we are left alone once again by the international community," he said.

Inbar predicts any action would probably happen before the November elections.

A sign came during Prime Minister Benjamin Netanyahu's recent visit to the United States when he made it clear the matter is quite urgent for Israel, while the Americans are taking their time.